Practice Test


1) Cathode rays are


2) Which is not true respect to cathode rays ?


3) Number of neutron in heavy hydrogen atom is


4) The orbit in Rutherford's model is


5) The orbit in Rutherford's model is


6) The credit of discovering neutron goes to


7) The mass of the neutron is of the order of


8) Atomic number is equal to the


9) What is the packet of energy called ?


10) Which of the following does not characterise X - rays?


11) Threshold energy is also called


12) Frequency of matter wave is equal to


13) An electron in H-atom in its ground state absorbs 1.50 times as much as energy as the minimum required for its escape ( 13.6 eV) from the atom. Thus kinetic energy given to emitted electron is


14) Visible spectrum extends from 400 nm (violet) to 750 nm (red). Hence frequency ratio is


15) The accelerating potential that must be imparted to a proton beam to give it an effective wavelength of 0.05 nm is (wt. of proton = 1.008 g)


16) Heaviest particle is


17) Nuclear theory of the atom was put forward by


18) Rutherford's scattering experiment is related to the size of the


19) When alpha particles are sent through a thin metal foil most of them go straight through the foil because


20) Electromagnetic radiation with maximum wavelength is


21) Rutherford's alpha rays scattering experiment eventually led to the conclusion that


22) The triad of nuclei which is isotonic is


23) Rutherford's experiments, which established the nuclear model of the atom, used a beam of


24) As we move away from nucleus, the energy of orbit


25) The radius of the atom is of the order of


26) 1 erg of energy corresponds to


27) Sodium chloride imparts a yellow colour to the Bunsen flame. This can be interpreted due to the


28) With increasing principal quantum number, the energy difference between adjacent energy levels in H atom


29) Splitting of spectral lines under the influence of magnetic field is called


30) The first emission line in the atomic spectrum of a hydrogen in the Balmer series appears at


31) The r is the radius of first orbit, the radius nth orbit of the H atom will be


32) The electron in an atom


33) The value of Planck's constant is


34) Who modified Bohr's theory by introducing elliptical orbits for electron path ?


35) The third line of the Balmer series, in the emission spectrum of the hydrogen atom, is due to transition from the


36) As the nuclear charge increases from neon to calcium, the orbital energies


37) The energy of the first electron in helium will be


38) In the Bohr's orbit, what is the ratio of total kinetic energy and total energy of the electron ?


39) The radius of second Bohr's orbit is


40) The energy of hydrogen atom in its ground state is -13.6 eV.The energy of the level corresponding to the quantum number n = 5 is


41) For the energy level in an atom, which one of the following statements is correct ?


42) According to Bohr's theory, the energy required for the transition of H atom from n=6 to n=8 state is


43) The value of the energy for the first excited state of hydrogen will be


44) Time taken for an electron to complete one revolution in the Bohr orbit of hydrogen atom is


45) In hydrogen atom, energy of first excited state is -3.4 eV. Find out the K. E. of the same orbit of hydrogen atom.


46) The one electron species having ionisation energy of 54.4 eV is


47) What is the number of revolutions of an electron in second Bohr's orbit of H-atom in one second ?


48) What is the angular momentum of H-atom orbit if its electron energy is -3.4 eV ?


49) If the electron in a hydrogen atom drops from the n = 6 to the n = 4 level, the radiation emitted is in which series of lines in the spectrum of atomic hydrogen ?


50) Angular momentum of an electron in the n th orbit of hydrogen atom is given by


51) In a hydrogen atom, if the energy of an electron in the ground state is 13.6 eV, then that in the 2 nd excited state is


52) Bohr's model can explain


53) If the speed of electron in Bohr's first orbit of hydrogen atom be x, then speed of the electron in 3rd orbit is


54) The energy of an electron in the first Bohr's orbits of H atom is -13.6 eV.The possible energy value (s) of the excited state (s) for electron in Bohr's orbits of hydrogen is (are)


55) The radius of which of the following orbits is same as that of the first Bohr's orbit of hydrogen atom ?


56) Which of the following expressions gives the de Broglie relationship ?


57) Wave nature of electrons was demonstrated by


58) If uncertainty in the position of electron is zero, the uncertainty in its momentum would be


59) The de-Broglie wavelength of a particle with mass 1 g and velocity 100 m/s is


60) Uncertainty in position and momentum are equal. Uncertainty in velocity is


61) If the radius of first Bohr orbit is x, the de-broglie wavelength of electron in 3 rd orbit is nearly


62) The uncertainty principle and the concept of wave nature of matter was proposed by....... and ..... respectively


63) The de-Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately


64) Which of the following relates to photons both as wave motion and as stream of particles ?


65) The wavelength associated with a golf ball weighing 200 g and moving at a speed of 5 m /h is of the order


66) The magnetic quantum number represents


67) The principal quantum number, n describes


68) Subsidiary quantum number specifies


69) No two electrons in an atom will have the four quantum numbers same. This statement is known as


70) "The exact path of electron in 2p-orbital cannot be determined". The above statement is based upon


71) No two electrons in an atom can have


72) Azimuthal quantum numbers determines the


73) In a set of degenerate orbitals the electrons distribute themselves to retain similar spin as far as possible. This statement is attributed to


74) The total number of orbitals in a shell with principal quantum numbers 'n' is


75) The electronic configuration of an atom / ion can be defined by the following


76) Which of the following orbitals have a dumb-bell shape?


77) A 4f orbital has


78) The number of electrons in the M Shell of the elements with atomic number 24 is


79) The electron present in K-Shell of the atom will differ in


80) For a given principal level n = 4, the energy of its sub -shell is of the order


81) The maximum number of electrons in a sub shell is given by the expression


82) Which of the following is not possible?


83) An electron has pricipal quantum number 3. The number of it's (i) subshells and (ii) orbitals would be respectively?


84) Which of the following has same number of electrons in the last shell?


85) The maximum number of electrons in a subshell for which l = 3 is


86) The quantum numbers for the after electrons of an atom are given by n = 2; l = 0; m = 0; s = 1/2. The atom is


87) The maximum number of electrons in p-orbital with n = 6; m = 0 is


88) Indicate which electronic configuration amongest the following correcltly represents the sulphur atom ?


89) Which quantum number is sufficient to describe the electron in hydrogen atom ?


90) When the azimuthal quantum number l=1, the shape of the orbital will be


91) Which one of the following shows the correct electronic configuration of the outermost shell in insert gases ?


92) The correct set of quantum numbers for the unpaired electron of chloride atom is


93) The correct set of quantum numbers for the unpaired electron of chloride atom is


94) The valence orbital configuration of an element with atomic number 23 is


95) Which of the following electronic configurations is not possible ?


96) Electronic configuration of calcium atom can be written as


97) Which of the following sets of quantum numbers is not possible ?


98) An electron has a spin quantum number +1/2 and a magnetic quantum number -1. It cannot be present in


99) The set of quantum number not applicable to an electron is


100) The quantum number values for the designation 3 d are


101) For which of the following sets of quantum numbers an electron will have the highest energy ?


102) Which of the following has more unpaired d-electrons ?


103) The correct set of quantum numbers for 4d-electrons is


104) The ground state electronic configuration of chromium is


105) Which of the following represents noble gas configuration ?


106) The number of electrons in 3d shell for element with atomic number 26 is


107) The total number of possible values of magnetic quantum number for the value of l = 3 is


108) Which one of the following pairs of atoms / atom - ion have identical ground state configuration ?


109) If the value of principal quantum number is 3, the total possible value for magnetic quantum number will be


110) The number of spherical nodes in 3p orbitals are


111) The four quantum numbers of the valency electron of potassium are


112) In which of the following pairs, the number of electrons in the outermost shell are different ?


113) Electronic configuration of most electronegative element is


114) Which of the following sets of quantum numbers belongs to highest energy ?


115) For how many orbitals, the quantum numbers n = 3, l = 2, m = +2 are possible ?


116) The nineteenth electron of chromium has which of the following set of quantum number ?


117) The correct order of increasing energy of atomic orbitals is


118) Number of orbitals present in 3rd shell is


119) The atomic number of an element is 35. What is the total number of electrons present in all the p-orbitals of the ground state atom of that element?


120) An element M has atomic mass 19 and atomic number 9.It's ion is represented by


121) Which of the following is not isoelectronic?


122) The total number of electrons present in all the s-orbitals, all the p-orbitals and all the d-orbitals of cesium ion are respectively


123) In the ground state, an element has 13 electrons in its M shell. The element is


124) Which of the following ions has the maximum magnetic moment?


125) Which of the following electronic configurations is not possible according to Hund's rule ?


126) One of the following pairs of ions have the same electronic configuration ?


127) Two electron in the same atomic orbital can be distinguished by their


128) Which of the following element's outermost orbits last electron has magnetic quantum number m = 0 ?


129) Among the following series of transition metal ion, the one where all metal ions have same 3d electronic configuration is


130) For d- electron, the orbital angular momentum is


131) Find the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25


132) The atomic numbers of elements X, Y and Z are 19, 21 and 25 respectively. The number of electrons present in the 'M' shells of these elements follow the order


133) which of the following arrangements of electrons is most likely to be stable ?


134) Hund's rule deals with the distribution of electrons in


135) Chloride ion and potassium ion are isoelectronic. Then


136) For f-orbital, the values of m are


137) Correct energy value order is


138) The highest number of unpaired electrons are present in


139) Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers l = 1 and l = 2 are respectively.


140) Which of the following sets of quantum numbers is correct for an electron in 4 f - orbital ?


141) Which of the following statements in relation to the hydrogen atom is correct ?


142) In a multi-electron atom, which of the following orbitals described by the three quantum numbers will have the same energy in the absence of magnetic field and electric fields ?
(A) n = 1, l = 0, m= 0
(B) n = 2, l = 0, m= 0
(C) n = 3, l = 1, m= 1
(D) n = 3, l = 2, m = 1
(E) n = 3, l = 2, m= 0


143) Which of the following has non - spherical sub - shell of electron ?


144) The principal quantum number of an atom is related to the


145) Any p-orbital can accommodate up to


146) The electron level which allows the hydrogen to absorb photons but not to emit is


147) Which one of the following sets of quantum number represents an impossible arrangement ?


148) The orbital diagram in which Aufbau principle is violated is


149) The correct of quantum numbers for the unpaired electron of Cl atom is


150) The quantum number not obtained from the Schrodinger's wave equation is


151) The outer shell configuration of the most electronegative element is


152) Which combination of quantum numbers n, l, m, s for the electron in an atom does not provide a permissible solution of the wave equation ?


153) Which of the following is violation of Pauli's exclusion principle ?


154) From the given sets of quantum numbers the one that is inconsistent with the theory is


155) Which of the following has maximum number of unpaired electron ?


156) The electron identified by quantum number n and l,
(i) n = 4, l = 1 (ii) n = 4, l = 0 (iii) n = 3, l = 2 (iv) n = 3, l = 1
can be placed in order of increasing energy, from the lowest to highest, as


157) The quantum numbers +1/2 and -1/2 for electron spin represents


158) Identify the least stable among the following.


159) How many structures of F are possible ?


160) Radial nodes present in 3s and 2p-orbital are respectively.


161) Electromagnetic radiation with maximum wavelength is


162) The ionization potential of hydrogen from ground state to the first excited state is


163) The mass of proton is 1840 times of electron, its potential difference is 1 kV. The kinetic energy of proton is


164) The presence of 3 unpaired electrons in N atom can be explained by


165) A cricket ball of 0.5 kg. is moving with a velocity of 100 m/sec. The wavelength associated with its motion is


166) The number of radial nodes in 5d is


167) The H-spectrum shows


168) Which of the following statements does not form a part of Bohr's model of hydrogen atom ?


169) Electrons will first enter into the set of quantum numbers n = 5, l = 0 or n = 3, l = 2


170) Which of the following is non - permissible ?


171) The following quantum numbers are possible for how many orbitals ? n =3, l = 2, m = +2.


172) In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen ?


173) Which of the following is correctly matched ?


174) In which of the following orbital diagrams are both Pauli's exclusion principle and Hund's rule violated ?


175) Which of the following sets of quantum numbers represents the highest energy of an atom ?


176) Nucleus of an atom was discovered by


177) Discharge tube experiments demonstrate the emission of certain invisible rays from


178) Cathode rays were named as electrons by


179) Cathode rays have


180) Protons were discovered by_______


181) Which statement is WRONG about anode rays?


182) Which of the following statement is wrong?


183) The charge to the mass ratio [e/m] of positive particles


184) The mass of a neutron is


185) Neutrons are present in all atoms except


186) Atomic number of an element is equal to the number of


187) The number of electrons and neutrons of an element is 18 and 20 respectively. Its atomic mass is


188) Which scientists showed that atomic number represents the number of protons in the nucleus of an atom?


189) The atomic weight and atomic number of an element are A and Z respectively. The number of neutrons in the atom of that element is calculated as


190) The introduction of a neutron into the nucleus of an atom would lead to a change in


191) Which of the following has same position in periodic table?


192) The postulate that all the atoms of an element are exactly alike was proved wrong with the discovery of


193) Antoine Becquerel proved that atoms are divisible with the help of his famous discovery of


194) When alpha particles are sent through a thin metal foil, most of them go straight through the foil because


195) Who discovered the nucleus of an atom?


196) Rutherford's experiment established that


197) The wavelength of a spectral line for electron transition is inversely related to


198) The phenomenon of splitting of spectral lines under the influence of the magnetic field is known as


199) When an electron jumps from lower energy level to higher energy level


200) In which case, the wavelength of the radiation emitted will be minimum?


201) Bohr's orbits are called stationary orbits because


202) Which one of the following statement is incorrect?


203) When electrons revolve in stationary orbits,


204) Which among the following transition will give Lyman series in the hydrogen line spectrum?


205) The spectral line obtained when an electron jumps from n= 6 to n= 2 level in hydrogen atom belongs to the


206) Which of the corresponding regions of the spectral lines of hydrogen atom is not correct?


207) Bohr model of atom can explain


208) Brackett series are produced when the electrons from the outer orbits jump to


209) According to Bohr's atomic model, P shell contains_______ electrons.


210) The dual nature of radiations was proposed by


211) Which of following is not a characteristic of Planck's quantum theory of radiation?


212) Which of the following statement concerning light is false?


213) According to de Broglie equation, wavelength of electron is


214) The de-Broglie equation suggests that an electron has


215) Heisenberg's uncertainty priciple rules out the exact simultaneous measurement of


216) A region in space around the nucleus of an atom where the probability of finding an electron is maximum is called


217) The quantum number not obtained from the solution of Schrodinger wave equation is


218) The probability of finding an electron at the nucleus is


219) Which of the following sets of quantum number is not possible for 23rd electron of Cr (At. No. 24)?


220) How many quantum numbers are required to define the electron in atom?


221) The possible subshells in n = 3 energy shell are


222) The principal quantum number n describes the


223) The angular momentum of an electron in atomic orbital depends upon the


224) The total number of orbitals in the fifth energy level is


225) To give a designation to an orbital, we need


226) The designation of a subshell with n= 4 and l= 3 is


227) 2p orbitals have


228) The two electrons present in an orbital are distinguished by


229) The value of azimuthal quantum number for electrons present in 4p - orbitals is


230) If the value of azimuthal quantum number of an electron is 2, then which of the following value of magnetic quantum numbers is not permissible?


231) If m has seven values, the value of azimuthal quantum number should be


232) The principal quantum number of an atom is related to the


233) The azimuthal quantum number is related to


234) Principal, azimuthal and the magnetic quantum numbers are respectively related to


235) Magnetic quantum number gives


236) Principal quantum number describes the


237) Which of the following orbitals does not exist?


238) How many electrons can have n = 4 and l = 2?


239) The maximum number of electrons in p-orbital with n = 6, m = 0 is


240) The electrons present in K-shell of the atom will differ in


241) Value of l = 1 represents________


242) The maximum number of electrons in s, p and d- subshells are


243) In s orbital as the value of n increases, the size of the s orbital


244) Which shape is associated with the orbital designated by n = 2, l = 1?


245) The shape of the orbital with the value of l = 2 and m = 0 is


246) For a dumb-bell shaped orbital, the value of l is


247) The order of filling of electrons in the orbitals of an atom will be


248) The shape of s- orbital is


249) All ________ orbitals are non- directional and spherically symmetrical.


250) when 3d orbitals are completely filled, new electron will enter in


251) What do you mean by degenerate orbitals?


252) Hund's rule deals with the distribution of electrons in


253) The Aufbau principle implies that a new electron will enter an orbital for which


254) The number of unpaired electrons in chromium ( Z=24) is


255) The tendency of an electron to exchange energy is _______ when the subshell is either half filled or completely filled.


256) According to Dalton's theory, atoms of different elements


257) Canal rays is a beam of


258) Electrons, protons and neutrons are known as ________ particles of atom


259) The electrons placed in the different shells of an atom of an element are… K-shell: 2 electrons, L-shell: 8 electrons, M-shell: 4 electrons. The atomic number of the element is


260) which of the following is the correct statement for isotopes?


261) J. J Thomson proposed that an atom has ______ shape.


262) Which of the following statement about spectral series is incorrect?


263) The maximum number of electrons in f- subshell is


264) The photoelectric emission from a surface starts only when the light incident upon the surface has a certain minimum


265) The total number of subshell in the 4th shell is


266) Which of the following statement regarding the probability of finding the electron in p-orbital is wrong?


267) Stability of completely filled and half filled subshell can be explained on the basis of


268) Experiments revealing that atom is composed of fundamental particles rejected_________model of atom.


269) Which of the following statements about quantum numbers is wrong?


270) The conclusion that an orbital can accommodate only two electrons is derived from


271) ______ principle limits the number of electrons in any orbital of an atom.


272) " The exact path of electron in 2p-orbital cannot be determined". This statement is based upon


273) In a given atom, no two electrons can have the same values for all the four quantum number. This is called


274) Electrons were discovered by


275) The conclusion that every additional electron enters the orbital with lowest possible energy has been drawn from


276) Neutron is denoted by


277) Which of the following has more electrons than neutrons?


278) The value of Planck's constant is


279) Which experimental observation correctly accounts for the phenomenon? (read as Experimental observation : Phenomenon)


280) Which of the following gave the idea of a nucleus of the atom?


281) Which of the following expression imposes the condition of quantization of energy of an electron in an atom?


282) According to Bohr's theory the angular momentum of an electron in the fourth orbit is


283) The energy of an atom in the 3rd orbit is -E. The energy of an electron in the first orbit will be


284) The value of Rydberg constant is


285) Which of the following is false regarding Bohr's model?


286) To which electron transition between Bohr orbitals in hydrogen does the second line in the Balmer series belong?


287) The correct expression derived for the energy of an electron in the nth energy level of H-atom is


288) Which of the following statement is incorrect?


289) The unit of frequency of radiation is


290) Which of the following is not correct?


291) Mathematically, Heisenberg's uncertainty principle can best be explained by


292) The number of electronic subshells in the nth quantum level are


293) The number of orbitals in any shell (n) is equal to


294) The maximum number of electrons present in any main energy level is given by


295) The number of electrons in a sub shell is equal to


296) Which of the following sets of quantum number is not permitted?


297) Which d-orbital does not have four lobes?


298) Which of the following statement is correct?


299) Which of the following configuration is incorrect?


300) The correct electronic configuration of nitrogen is


301) Which one of the following shows the correct electronic configuration of the outermost shell in inert gas?


302) In uni electron system, the wave number of a spectral line is directly proportional to


303) Which of the following represents the de Broglie relation?


304) Which of the following arrangements of electrons is most likely to be stable?


305) Cathode rays have same charge to mass ratio as


306) X-rays were discovered by:


307) Two electrons in the same orbital may be identified with:


308) An electron has principal quantum number 3. The number of its (i) subshells and (ii) orbitals would be respectively:


309) Maximum number of electrons in a subshell of an atom is determined by the following:


310) Particle having mass 200 times that of an electron is:


311) Which of the following has the maximum number of unpaired electrons?


312) An electron from one Bohr stationary orbit can go to next higher orbit


313) How many neutrons are present in tritium nucleus?


314) The statements, which is/are correct:


315) Zeeman effect refers to the


316) In potassium the order of energy level for 19th electron is:


317) A strong argument for the particle nature of cathode rays is that they:


318) What is the ration of mass of an electron to the mass of a proton?


319) As the number of orbit increase from the nucleus, the difference between the adjacent energy levels:


320) The orbital angular momentum of a p-electron is given as:


321) Transition from n = 2, 3, 4, 5… to n = 1 is called


322) If the total energy of an electron in a hydrogen like atom in an excited state is -3.4 eV, then the de Broglie wavelength of the electron is:


323) Which d-orbital does not have four lobes?


324) The nucleus of an atom contains


325) Positive charge in an atom is:


326) Total number of electrons present in acetylene molecule is:


327) An ion which has 18 electrons in the outermost shell is:


328) The maximum number of electrons in a p-orbital with n = 6 and m = 0 can be:


329) Energy of photon of visible light is


330) The photoelectric effect occurs only when the incident light has more frequency than a certain minimum:


331) For which of the following, the radius will be same as for hydrogen atom having n = 1?


332) The volume of a proton is approximately;


333) Normally, the time taken in the transition is :


334) When the value of azimuthal quantum number is 3, magnetic quantum number can have values:


335) Positive rays or canal rays are:


336) X-rays do not show the phenomenon of :


337) Rydberg is :


338) Which is not deflected by magnetic field:


339) Increase in the frequency of the incident radiations increases the:


340) One electron volt is:


341) A quanta will have more energy, if :


342) The number of waves in an orbit are


343) Which of the following electron transition in hydrogen atom will require largest amount of energy?


344) The principal quantum number n can have integral values ranging from:


345) The present atomic weight scale is:


346) Which one of the following set of quantum numbers is not possible for electron in the ground state of an atom with atomic number 19?


347) The total number of electrons present in all the 's' orbitals, all the 'p' orbitals and all the 'd' orbitals of cesium ion are respectively


348) What is the lowest energy of the spectral line emitted by the hydrogen atom in the Lyman series? (h = Planck's constant, c = velocity of light, R = Rydberg's constant).


349) The total number of electrons present in all the 's' orbitals, all the 'p' orbitals and all the 'd' orbitals of cesium ion are respectively, the velocity acquired by the electron will be;


350) Which is not electromagnetic radiation?


351) Magnetic quantum number for the last electron in sodium is:


352) The Heisenberg's uncertainty principle can be applied to


353) Which one of the following sets of quantum numbers represents the highest energy level in an atom?


354) Isotopes are


355) Which consists of particle of matter?


356) Which element possess non-spherical shells?


357) Splitting of spherical lines when atoms are subjected to strong electric field is called:


358) The velocity of electron in first orbit of H-atoms as compared to the velocity of light is


359) Which best describe the emission spectra of atomic hydrogen?


360) In the ground state of the H-atom, the electron is :


361) Which wave property is directly proportional to energy of electromagnetic radiation:


362) Mass of an electron is :


363) The number of electrons in a neutral atom of an element is equal to its:


364) The number of electrons in a neutral atom of an element is equal to its:


365) Which is the correct outermost shell configuration of chromium?


366) Which of the following ion will show colour in aqueous solution?


367) The highest number of unpaired electrons are in


368) Maximum number of electrons in an orbit is given by:


369) Compared to the mass of lightest nuclei, the mass of an electron is only (app.)


370) The electronic configuration of the element which is just above the element with atomic number 43 in the same particle group is:


371) The electric configuration of element with atomic number 24 is


372) The order of filling of electrons in the orbital of an atom will be:


373) Which one of the following pair of atoms/atom-ion have identical ground state configuration?


374) A gas absorbs photon of 355 nm and emits at two wavelengths. If one of the emission is at 680 nm, the other is at


375) Compared to mass of lightest nucleus the mass of an electron is only:


376) Bohr's model violates the rules of classical physics because it assumes that:


377) Which of the following statements does not form a part of Bohr's model of hydrogen atom?


378) Bragg's equation will have no solution, if:


379) Size of the nucleus is:


380) Penetration power of proton is:


381) Which of the following elements has least number of electrons in its M-shell?


382) The mass of an electron is m, its charge e and it is accelerated from rest through a potential difference V. The kinetic energy of the electron in joules will be :


383) In an atom wave mechanics suggests that electrons:


384) Splitting of spectrum lines in magnetic field is


385) Which of the following is non-permissible?


386) Which electronic configuration does not follow the Pauli's exclusion principle?


387) Which of the following atoms has same number of protons and neutrons in its nucleus?


388) The ratio of the difference in energy between the first and the second Bohr orbit to that between the second and the third Bohr orbit is


389) In an atom with atomic number 29, mass number 59, the number of electrons is:


390) In which orbital electron is most tightly bound to the nucleus?


391) Which of the following is correctly matched?


392) Threshold wavelength depends upon:


393) Which of the following is not possible?


394) The atomic radius is of the order of :


395) Light, a well known form of energy, is treated as a form of matter, by saying that it consist of :


396) When the azimuthal quantum number has the value of 2, the number of orbitals possible are


397) Compared to the lightest atom the heaviest atom weighs:


398) In a hydrogen atom, if energy of an electron in ground state is -13.6 eV, then that in the 2nd excited state is:


399) Which of the following sets of quantum number is correct for an electron in 4f-orbital?


400) If the following particles travel with equal speed, then for which particle the wavelength will be longest?


401) The orbital cylindrically symmetrical about x-axis is:


402) The ratio of radii of two nuclei with mass numbers 27 and 64 is


403) The orbital with maximum number of possible orientations is:


404) The orbital closest to the nucleus is:


405) Isoelectronic pair among the following is


406) The number of valence electrons in completely excited sulphur atom is:


407) The work-function for photoelectric effect :


408) Line spectra is characteristic of :


409) An improbable configuration is:


410) The wave number of radiation of wavelength 500 nm is:


411) Which of the following is the correct form of Schrodinger wave equation?


412) If n = 6, the correct sequence for filling of electrons will be:


413) Which one is not true for the cathode rays?


414) Moseley's law is : (a and b are constants, Z = atomic number, v = frequency)


415) From the discharge tube experiment, it is concluded that:


416) Which atom has as many as s-electrons as p-electrons?


417) Mosley's name is connected with the discovery of :


418) For a Bohr atom angular momentum M of the electron is (n = 0, 1, 2, ...)


419) When 3d-orbital is complete, the newly entering electron goes into:


420) Which of the followings sets of quantum numbers represents the highest energy of an atom?


421) When an electron jumps from L- level to M - level, there occurs:


422) If the kinetic energy of an electron is increased four times, the wavelength of the de-Broglie wave associated with it would becomes


423) The discovered of neutrons become very late because


424) "Positronium" is the name given to an atom-like combination formed between:


425) The nucleus of helium contains:


426) Photoelectric effect shows:


427) When high speed electrons strike a target:


428) The de Broglie wavelength of a particle with mass 1 g and velocity 100 m/s is:


429) Photoelectric effect can be caused by :


430) Deflection back of a few particles on hitting thin foil of gold shows that


431) An atom has 2 electrons in K-shell, 8 electrons in L-shell and 6 electrons in M-shell. The number of s-electrons present in the element is:


432) The angular momentum of an electron in 2 p-orbital is :


433) Which set has the same number of s-electrons?


434) Which wavelength falls in a X-rays region?


435) Of the following transitions in hydrogen atom, the one which gives an absorption line of lowest frequency is :


436) Which is not in accordance to aufbau principle?


437) Which of the following has more number of unpaired electron?


438) The scientist who proposed the atomic model based on the quantization of energy for the first time is


439) The energy of the electron in first Bohr's orbit is -13.6eV. The energy of the electron in its first excited state is


440) Cathode rays are produced when the pressure in the discharge tube is of the order of :


441) Number of electrons in nucleus of an element of atomic number 14 is:


442) The study of photoelectric effect is useful in understanding:


443) The ratio of radius of III and IV Bohr's orbits in hydrogen atom is:


444) When an electron of charge e and mass m moves with velocity u about the nuclear charge Ze in the circular orbit of radius r, the potential energy of the electron is given by:


445) Which diagram best represents the appearance of the line spectrum of atomic hydrogen in the visible region?


446) If the electron of a hydrogen atom is present in the first orbit, the total energy of the electron is


447) The number of elliptical orbits, including circular orbits in the M-shell of an atom is:


448) Wave mechanical model of the atom depends upon:


449) The orbital angular momentum of an electron revolving in a p-otbital is


450) The velocity of a photon is:


451) Possible values of 'm' for a given value of n are:


452) Common name for proton and neutron is


453) A node is a surface on which the probability of finding an electron is:


454) In photoelectric effect, the photo-current:


455) Possible number of orientations of a subshell is:


456) The orientation of an atomic orbital is governed by:


457) The ratio of the radius of the orbit for the electron orbiting the hydrogen nucleus to that of an electron orbiting a deuterium nucleus is:


458) Which of the following sets of quantum numbers is correct for an electron in 4f-orbital?


459) The electronic energy levels of the hydrogen atom in the Bohr's theory are called:


460) A photoelectric cell is a device, which :


461) An f-shell containing 6 unpaired electrons can exchange


462) Angular momentum of an electron in the n th orbit of hydrogen atom is given by


463) Radius of nucleus is proportional to …where A is mass number


464) Which possesses an inert gas configuration?


465) Choose the correct statement among the following


466) In ground state of chromium atom (Z = 24) the total number of orbitals populated by one or more electrons is:


467) The observation that the ground state of nitrogen atom has 3 unpaired electrons in its electronic configuration and not otherwise is associated with


468) Which set is not correct?


469) The mass of a neutron is of the order of:


470) As an electron is brought from an infinite distance close to the nucleus of the atom, the energy of the electron-nucleus system:


471) Beryllium's fourth electron will have the four quantum numbers:


472) The electrons would go to lower energy levels first and then to higher energy levels according to which of the following?


473) Which among the following species have the same number of electrons in its outermost as well as penultimate shell?


474) Photons of energy 6 eV are incidented on a potassium surface of work function 2.1 eV. What is the stopping potential?


475) When the speed of electron increase, the specific charge:


476) If uncertainty in position and momentum are equal, then uncertainty in velocity is:


477) Two electron in an atm of an element cannot have:


478) The energy of electromagnetic radiation depends on:


479) Which type of radiation is not emitted by the electronic structure of atoms?


480) The difference between ions and atoms is of:


481) The statements are valid for :
(i) In filling a group of orbitals of equal energy, it is energetically preferable to assign electrons to empty orbitals rather than pair them into a particular orbital
(ii) When two electrons are placed in two different orbitals, energy is lower if the spins are parallel


482) In the absence of magnetic field p-orbitals are known as… fold degenerate


483) In hydrogen spectrum least energetic transition of electrons are found in:


484) The ground state term symbol for an electronic state is governed by


485) In hydrogen atom, which energy level order is not correct:


486) One energy difference between the states n=2 and n=3 is E eV, in hydrogen atom. The ionisation potential of H atom is:


487) The atomic number of an element is 17. The number of orbitals containing electron pairs in the valency shell is:


488) Which statement is relating to the spectrum of H atom is false ?


489) The de Broglie wavelength associated with a material particle is:


490) Naturally occurring elements are mixtures of:


491) 1 fermi is equal to :


492) When an electron moves from higher orbit to a lower orbit … is produced


493) The Atomic number of the element having maximum number unpaired 3p - electrons is


494) A photon in X region is more energetic than in the visible region X is:


495) The stability of ferric ion is due to


496) According to aufbau principle, the correct order of energy of 3d, 4s and 4p-orbitals is


497) The maximum wavelength of light that can excite an electron from first to third of hydrogen atom is


498) The H-spectrum show


499) The total number of protons present in all the elements upto 'Zn' in the periodic table is:


500) Orbitals processing the same energy are called:


501) Which set has the same number of unpaired electrons in their ground state?


502) The atomic number of an element is 35 and its mass is 81. The number of electrons in its outermost shell is


503) According to Dalton's atomic theory, the smallest particle which is capable of independent existence is:


504) The possibility of finding an electron in an orbital was conceived by:


505) Which statement is/are correct?


506) The incorrect statement about bohr's orbit of hydrogen is atom is


507) When electrons in N-shell of excited hydrogen atom return to ground state, the number of possible line spectrum is


508) The electrons occupying the same orbital have always spin.


509) The energy of hydrogen atom in its ground -13.6 eV. The energy of the level corresponding to the quantum number n = 5 is


510) According to Bohr's theory, the angular momentum for an electron of 5th orbit is


511) Correct set of four quantum number for valance electron of rubidium (Z = 37) is


512) The total number of orbitals possible for principal quantum number n is


513) which does not characterise X-rays?


514) The velocity of an electron placed in third orbit of H atom, will be


515) The orbital angular momentum of an electron in 2s orbital is


516) In the atomic spectrum of hydrogen the series lines observed in the visible region is


517) According to Bohr's model of hydrogen atom


518) Which transition of electron in the hydrogen atom emits maximum energy?


519) The quantum number that does not describe the distance and the angular disposition of the electron


520) In H-atom ,the electron is de-excited from 5th shell to 1st shell. How many different lines may appear in line spectrum?


521) The electronic configuration with maximum energy will be


522) The orbital diagram in which aufbau principle is violated is


523) The number of spherical nodes in 3p orbital is


524) Ultraviolet light of 6.2 eV falls on aluminium surface (work function = 4.2 eV). The kinetic energy (in joule) of the fastest electron emitted is approximately.


525) The value of quantum numbers for the outermost electron in scandium (Sc = 21) are;


526) Each p-orbital and d-orbital except one has lobes respectively as:


527) The wavelength of radiations emitted when H in atom,electrons fall from electron to stationary state 1 is:


528) Select the odd man


529) Assuming the velocity be same, which sub-atomic particle possesses smallest de Broglie wavelength;


530) The chromium has different electronic configuration then what is expected according to aufbau principle because


531) If the ionisation potential for hydrogen atom is 13.6eV, then the wavelength of light required for the ionisation of hydrogen atom would be:


532) Bohr's atomic theory gave the idea of


533) Which species has more electrons than protons?


534) Electronic configuration of niobium (Nb = 41) is:


535) X-rays cannot penetrate through a sheet of:


536) How many electrons can fit into the orbitals that comprise the 3rd quantum shell?


537) The total values of magnetic quantum number of an electron when the value of n = 2 is:


538) The binding energy of the electron in the lowest orbit of the hydrogen atom is 13.6 eV. The energies required in eV to remove an electron from three lowest orbits of the hydrogen atom are:


539) The best metal to be used for photoemission is:


540) The probability of finding the electron in the orbital is


541) The correct de Broglie relationship is:


542) The one electron species having ionisation energy of 54.4 eV is


543) Electronic configuration of tritium is :


544) The correct set of quantum numbers (n,l and m respectively) for the unpaired electron of chlorine atom is


545) Total number of unpaired electrons, in an unexcited atom of atomic number 29 is:


546) The work function for a metal is 4 eV. To emit a photoelectron of zero velocity from the surface of the metal, the wavelength of incident light should be:


547) The wave number of the first line in the Lyman series in hydrogen spectrum is


548) The nodes present in 3p-orbitals are


549) Electronic configuration of deuterium atom is


550) Which of the following sets of quantum numbers is correct?


551) Correct energy value order is


552) Which hydrogen like species will have same radius as that of Bohr orbit hydrogen atom?


553) The expression Ze gives :


554) Which has the highest number of unpaired electrons?


555) The ratio between the neutrons present in carbon and silicon with respect to atomic masses of 12 and 28 is:


556) The last electron placed in the third (n = 3) quantum shell for:


557) The number of spectral lines that can be possible when electrons in 7th shell in different hydrogen atoms return to the 2nd shell, is


558) The value of Rydberg constant is


559) In absence of Pauli exclusion principle, the electronic configuration of Li in ground state may be:


560) Which relates to light only as stream of particles?


561) Who introduced the concept of electron spin?


562) The unit of wavelength (nm) is equal to:


563) Mass of neutron is … times the mass of electron


564) The highest excited state that unexcited hydrogen atom can reach when they are bombarded with 12.2 eV electron is :


565) The total number of atomic orbitals in fourth energy level of an atom is:


566) The orbital angular momentum of an electron in a d-orbital is


567) The space between the proton and electron in hydrogen atom is:


568) Particles, which can be added to the nucleus of an atom without changing the chemical properties, are called:


569) When 4f-level of an atom is completely filled with electrons, the next electron will enter:


570) The total number of electrons that can be accommodated in all the orbitals having principal quantum number 2 and azimuthal quantum number 1 is:


571) Suppose a completely filled or half filled set of p or d-orbitals is spherically symmetrical. Point out the species, which is spherical symmetrical?


572) The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is


573) Which d-orbital has different shape from rest of all d-orbital?


574) Photoelectric effect is the phenomenon in which:


575) When the value of azimuthal quantum number is 1, magnetic quantum number can have values:


576) The H atom electron dropped from n = 3 to n = 2, then energy emitted is


577) The maximum number of sublevels, orbitals and electrons in N-shell of an atom are respectively


578) Millikan's oil drop experiment is used to find:


579) The maximum number of unpaired electrons present in 4f-energy level is:


580) The target used for production of X-ray beam must have:


581) According to Bohr's model of the hydrogen atom, the radius of a stationary orbit characterised by the principle quantum number n is proportional to:


582) Which one of the following has unit positive charge and 1 u mass?


583) Among the following sets of quantum numbers, which one is incorrect for 4d-electron?


584) An electrons is in one of the 3d-orbitals, which of the quantum number is not possible?


585) The momentum of a photon is p. The corresponding wavelength is:


586) Which one of the following sets of ions represents a collection of isoelectronic species?


587) An electron, a proton and an alpha particle have KE of 16E, 4E and E respectively. What is the qualitative order of their de-Broglie wavelengths?


588) The e/m ratio is maximum for:


589) The principle, which gives a way to fill the electrons in the available energy level is:


590) Which of the following has the maximum number of unpaired 'd' electrons?


591) Out of first 100 elements, number of elements having electrons in 3d-orbitals are:


592) Identify the least stable ion amongst the following


593) Mass number of atom represents the number of its:


594) Number of electrons in the outermost orbit of the element of atomic number 15 is:


595) Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atom in the ground state are excited by monochromatic light of energy 12.1 eV. The spectral lines emitted by hydrogen according to Bohr's theory will be:


596) The line spectrum observed when electron falls from the higher level into L-level is known as:


597) The angular momentum of electron of H-atom is proportional to:


598) Which set of quantum number represents the electron of the lowest energy?


599) Electron behaves both as a particle and a wave. This was proposed by


600) The number of waves in an orbit are


601) Which is not basic postulate of Dalton's atomic theory?


602) p-orbitals of an atom in presence of magnetic field are:


603) The valency orbital configuration of an element with Z = 23 is:


604) In 'aufbau principle', the term aufbau represents:


605) A particle of mass, 'm' when annihilated completely given an energy E equal to:


606) The correct set of four quantum number for the valence electron of rubidium (Z=37) is


607) An atom has net charge of -1. It has 18 electrons and 20 neutrons. Its mass number is:


608) A photon is:


609) Which orbital is dumb-bell shaped?


610) Which of the following is related with both wave nature and particle nature?


611) Aufbau principle does not give the correct arrangement of filling up of atomic orbital's in


612) Ordinary oxygen contains:


613) The approximate quantum number of a circular orbit of diameter, 20.6 nm of the hydrogen atom according to Bohr's theory is:


614) A p-orbital in a given shell can accommodate upto


615) An electron beam is accelerated through a potential difference of 10,000 volt. The de-Broglie wavelength of the electron beam is


616) Transition of electron from n = 3 to n = 1 level results in:


617) A cricket ball of 0.5 kg is moving with a velocity of 100 m/s. The wavelength associated with its motion is


618) The ratio of the masses of proton and neutron are:


619) The ratio between kinetic energy and the total energy of the electrons of hydrogen atom according to Bohr's model is:


620) If the mass number of an element is W and its atomic number is N, then:


621) Binding energy of hydrogen atom is 13.6 eV. The binding energy of a singly ionised helium atom is:


622) Neutron was discovered by:


623) For a particular value of azimuthal quantum number, the total number of magnetic quantum number values are given by


624) The relation between energy of a radiation and its frequency was given by:


625) The filling of 4p-sublevel starts in the element of atomic number:


626) The angular speed of the electron in the nth orbit of Bohr hydrogen atom is:


627) The chlorine atom differs from chloride ion in the number of:


628) Which orbital does not possess angular node?


629) The azimuthal quantum number for an electron in a 5d-orbital is:


630) According to Bohr's theory, the angular momentum for an electron of 3rd orbit is


631) Nuclides:


632) The de-Broglie equation applies


633) Which of the following electronic configuration is not possible?


634) The maximum energy is possessed by an electron, when it is present


635) Maximum number of electrons which can be accommodated in a g-subshell is:


636) The radii of two of the first four Bohr's orbits of the hydrogen atom are in the ratio 1∶4. The energy difference between them may be:


637) The compound in which cation is isoelectronic with anion is


638) If each hydrogen atom is excited by giving 8.4 eV of energy, then the number of spectral lines emitted is equal to:


639) The electronic configuration of silver atom in ground state is:


640) Which is correct in case of p-orbitals?


641) X-rays and γ-rays of same energies may be distinguished by:


642) A neutral atom always consist of :


643) The first emission line of Balmer series for H-spectrum has the wave no. equal to:


644) A photon of 300 nm is absorbed by a gas then re-emits two photons. One re-emitted photon has wavelength 496 nm, the wavelength of second re-emitted photon is:


645) Which statement does not form part of Bohr's model of the hydrogen atom?


646) If uncertainties in the measurement of position and momentum of an electron are equal, the uncertainty in the measurement of velocity is


647) Which of the following is correct for number of electrons, number of orbitals respectively in n-orbit?


648) The quantum number sufficient to describe the electron in H atom is:


649) If an isotope of hydrogen has two neutrons in its atom, its atomic number and mass number will be:


650) The speed of the cathode rays is:


651) Bohr model can explain


652) Which of the following statement is relation to the hydrogen atom is correct?


653) The nature of canal rays depends on:


654) Neutron possesses:


655) Cathode-ray tube is used in:


656) Non-directional orbital is


657) The maximum sum of the number of neutrons and proton is an isotope of hydrogen is :


658) The principal quantum number of an atom represents:


659) The specific charge for positive rays is much less than the specific charge for cathode rays. This is because:


660) The magnetic moment of electron in an atom (excluding orbital magnetic moment) is given by:


661) de Broglie equation is a relationship between:


662) Which electromagnetic radiation has extremely small wavelength?


663) The maximum number of 3d-electrons having spin quantum number s = +1/2 are:


664) Dimensions of Planck's constant are:


665) If helium atom and hydrogen molecules are moving with the same velocity, their wavelength ratio will be


666) All types of electromagnetic radiations possess same:


667) Which is not permissible subshell?


668) In Bohr's series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inner-orbit jumps of the electron for Bohr orbit in an atom of hydrogen?


669) Which represents the correct set up of the four quantum numbers of 4s-electron?


670) Ground state electronic configuration of nitrogen atom can be represented as


671) Electron in the atom are held by:


672) If the electron in the hydrogen atom is excited to n=5, the number of different frequencies of radiations which may be emitted is:


673) The uncertainty principle and the concept of wave nature of matter was proposed by … and … respectively


674) According to Bohr's theory, the angular momentum of an electron in 5th orbit is


675) Positron is:


676) Quantum theory was postulated by:


677) Which of the following expressions gives the de-Broglie relationship?


678) Three electrons in p-sublevel must have the quantum number:


679) The number of vacant d-orbitals in completely excited Cl atom is:


680) The mass number of an element is 23 and atomic number is 11. The number of protons, electrons and neutrons respectively present in the atom of the elements are:


681) The planck's constant has a unit of:


682) The quantum numbers of most energetic electron in Ne atom when it is in first excited state is:


683) The number of p-electrons in bromine atom is


684) Potassium ion is isoelectronic with the atom of:


685) Density of the electron is:


686) Cr has electronic configuration as


687) The number of electrons accommodated in an orbit with principle quantum number 2, is


688) The number of vacant orbitals of element with atomic number 14 is:


689) Which of the following is correct?


690) Energy of H-atom in the ground state is -13.6 eV, hence energy in the second excited state is


691) Nuclear theory of the atom was put forward by


692) Which of the following is not permissible arrangement of electrons in an atom?


693) An atom having even number of electrons may be:


694) Dual nature of particles was proposed by


695) In photoelectric effect, the number of photoelectrons emitted is proportions to


696) The number of radial nodes of 3s and 2p-orbitals are respectively


697) Correct set of four quantum numbers of a 4d-electron is:


698) The orbital angular momentum of an electron in 3s-orbital is


699) Which of the following statement is relation to the hydrogen atom is correct?


700) Atoms in hydrogen gas have preponderance of:


701) The energy of the electron at infinite distance from the nucleus in Bohr's model is taken a:


702) The maximum number of electrons possible in a sublevel is equal to:


703) The radius of second stationary orbit in Bohr's atoms is R. The radius of third orbit will be:


704) In photoelectric emission the energy of the emitted electrons is:


705) The triad of nuclei which is isotonic is


706) Angular momentum of an electron in an orbital is given by :


707) The charge on an electron was discovered by


708) In hydrogen spectrum most energetic transitions of electrons are found in:


709) Which property of elements is not a whole number?


710) Proton is :


711) Which of the following is Heisenberg uncertainty principle?


712) Which of the following make up an isotonic triad?


713) Which principle/rule limits the maximum number of electrons in an orbital to two?


714) Magnitude of kinetic energy in an orbit is equal to


715) The maximum number of atomic orbitals associated with a principal quantum number 5 is:


716) The magnetic quantum number for valency electron of sodium is:


717) Which pair has elements containing same number of electrons in the outermost orbit?


718) The electromagnetic radiation with maximum wavelength is:


719) An element contains:


720) Heaviest particle is:


721) The set of quantum numbers for the outermost electron for copper in its ground state is


722) Atom containing an odd number of electron is:


723) Amplification of electromagnetic waves by simulated emission of radiation produces:


724) In the discharge tube emission of cathode rays requires:


725) Which electron transition in a hydrogen atom requires the largest amount of energy?


726) The angular momentum of an electron in an atomic orbital is governed by the:


727) In Bohr's model of the hydrogen atom the ratio between the period of revolution of an electron in the orbit n = 1 to the period of revolution of the electron in the orbit n = 2 is:


728) Different lines in Lyman series of hydrogen spectrum lie in …. region


729) The atoms in a molecule vibrate around their mean position by stretching or bending out of place. These vibration and the energy they carry are studied by:


730) Maximum number of electrons present in "N" shell is:


731) Which electronic level will allow the hydrogen atom to absorb photon but not to emit?


732) The mass of electron moving with velocity of light is:


733) Which of the following particles moving with same velocity would be associated with smaller de-Broglie wavelength?


734) The electron configuration of the oxide ion is much most similar to the electron configuration of the


735) Stark effect refers to the


736) For which species, Bohr's theory does not apply:


737) Which of the subshell has double dumb-bell shape?


738) The lightest particle is


739) The radius of second Bohr's orbit of hydrogen atom is


740) Which set of phenomenon shown by the radiation proves the dual nature of radiation?


741) The hydrogen spectrum from an incandescent source of hydrogen is:


742) The path of deflection of electron beam is:


743) Which particle may be removed from a stable neutral atom with least energy change?


744) Visible spectrum of hydrogen shows that it exists in two different forms which are based on direction of spin of the:


745) Evidence for the existence of different energy levels in atom is supplied by:


746) Which are in the ascending order of wavelength?


747) The mass of one mole of electron is:


748) According to Bohr's postulates which quantity can take up only discrete values:


749) Which of the following reaction led to the discovery of neutrons?


750) The radius of which of the following orbit is same as that of the first Bohr's orbit of hydrogen atom?


751) Which has minimum number of unpaired d-electrons?


752) The total spin for atoms with atomic number 7, 24, 34 and 36 will be


753) A photo-sensitive metal is not emitting photo-electrons when irradiated. It will do so when threshold is crossed. To cross the threshold we need to increase :


754) Which neutral atom has 18 electrons in its outer shell?


755) Rutherford scattering formula fails for very small scattering angles because


756) 3 p-orbital has:


757) Rutherford's alpha particle scattering experiment eventually led to the conclusion that:


758) The d-orbital with the orientation along X and Y axes is called:


759) Which of the following transitions are not allowed in the normal electronic emission spectrum of an atom?


760) In an atom two electrons move around the nucleus in circular orbits of radii R and 4R. The ratio of the time taken by them to complete one revolution is:


761) The number of electrons and protons in an atoms of third alkaline earth metal is


762) In photoelectric effect the number of photo-electron emitted is proportional to :


763) Which of the following statements is wrong about cathode rays?


764) In an atom no two electrons can have the same value for all the quantum numbers. This was proposed by:


765) The minimum energy required to eject an electron from an atom is called:


766) As electron moves away from the nucleus, its KE:


767) A hydrogen atom in its ground state absorbs a photon. The maximum energy of such a photon is:


768) Wave nature of electrons was demonstrated by


769) The principal quantum number of H-atom orbital, if the electron energy is -3.4 eV, will be


770) No two electrons can have the same values of …. quantum numbers.


771) The first atom with incomplete d-shell is:


772) Particle nature of electron was experimentally demonstrated by


773) The difference in angular momentum associated with the electron in two successive orbits of hydrogen atom is:


774) The volume of nucleus is about:


775) The species having more electrons than neutrons is:


776) Which ion has the maximum magnetic moment?


777) Photoelectric effect was discovered by :


778) When light is directed at the metal surface, the emitted electrons:


779) The minimum real charge on of any particle, which can exist is:


780) An electron jumps from an outer orbit to an inner orbit with an energy difference of 3.0eV. What will be the wavelength of the line emitted?


781) Statement 1 : The charge to mass ratio of the particles in anode rays depends on nature of the gas taken in the discharge tube.
Statement 2 : The particles in anode rays carry positive charge.


782) Statement 1 : Only principal quantum number determines the energy of an electron in an orbital in sodium atom.
Statement 2 : For one electron system, the expression of energy is the same as that obtained in Bohr's theory.


783) Statement 1 : Kinetic energy of photoelectrons is directly proportional to the intensity of the incident radiation.
Statement 2 : Each photon of light causes the emission of only one photoelectrons.


784) Statement 1 : Radiant energy of quantum is given by E = h v.
Statement 2 : Quantum in the energy equation signifies the principal quantum number.